Relief-patterned metal article and a method of making same

ABSTRACT

A metal article is formed with a relief pattern on its surface by a method comprising shaping the metal article to deform the surface thereof such as by bending a flat sheet, then annealing the thus deformed article above the recrystallization temperature to cause enlargement of the crystal grains. The article is then deformed again, such as by being flattened to its original shape, whereafter the surface of the article is etched. There is produced on the surface a relief pattern which can appear to be raised in part and depressed in part.

Yoshida et a1.

June 24, 1975 1 RELlEF-PATTERNED METAL ARTICLE AND A METHOD OF MAKING SAME [75] Inventors: Kiyota Yoshida; Mizuo Ejima, both of Tokyo Japan [73] Assignee: Rikagaku Kenkyusho, Wako-shi.

Japan 122 Filed: May 29,1973

2| 1 Appl.No.:364,406

[30] Foreign Application Priority Data May 29, 1973 Japan .7 48-53218 [52] US. Cl l48/ll.5 R; 148/115 A; 148/32 [51] Int. Cl C22f 1/00; C22f 1/04 [58] Field of Search 148/1 1.5 A, 11.5 R, 32; 29/D1G. 30

[56] References Cited UNITED STATES PATENTS 2.941930 6/1960 Mostovych ct a1. 148/115 A Cl O2 0': l l \"l I l GRAIN n\ GRAIN BOUNDARY GRAIN I 3.773.576 11/1973 Pond .v 148/11.5A

Primary Examiner-W. Stallard Attorney, Agent, or FirmHaseltine, Lake & Waters [5 7] ABSTRACT A metal article is formed with a relief pattern on its surface by a method comprising shaping the metal article to deform the surface thereof such as by bending a flat sheet, then annealing the thus deformed article above the recrystallization temperature to cause enlargement of the crystal grains. The article is then deformed again, such as by being flattened to its original shape, whereafter the surface of the article is etched. There is produced on the surface a relief pattern which can appear to be raised in part and depressed in part.

9 Claims, 16 Drawing Figures GRAIN 111 GRAIN BOUNDARY PAIENIEIJJUII24|915 3.891.472 SIIEEI I 1 FIG, I Pew/I ART 0.: q; 21': a 9% o osg's GRAINII AINI GRAIN llI GRAIN BOUNDARY GRAIN BOUNDARY FI G. 3

GI I 4I I- I G'I 1 I v I v GRAIN n\ GRAIN I GRA|N111 GRAIN BOUNDARY GRAIN BOUNDARY PATENTEH JUN 2 4 m5 3 8 91' 47 2 SHEET 2 F|G.4A FIG. 4B

F I 6. 40 ii U PATENTEUJUH24 I975 3.891.472

SHEET 4 FIG.8A

FIG. 8B

FIG.8C

PATENTEUJIJH24 I975 3,891,472

SHEET 5 FIG.9

FIG.I2

RELIEF-PATTERNED METAL ARTICLE AND A METHOD OF MAKING SAME BACKGROUND 1. Field of the Invention This invention relates to a patterned metal article having a crystal pattern composed of crystal grains appearing on the surface of the article, and more specifically it relates to a relief-patterned metal article and to a method of making same, said relief-patterned article having a crystal pattern composed of either agglomerations of large-sized crystal grains or discrete large-sized crystal grains on at least a part of the surface of the article.

2. Prior Art It is well known that the crystal grains can be made to appear on a metal surface in the form of a pattern first by subjecting the metal to a slight deformation (of a magnitude ofa few percent), second by annealing the material thus deformed, and finally by subjecting the thus annealed material to etching. Also, it is well known that the shape and size of the crystal grain will vary with the degree of deformation, the annealing temperature and other operating parameters.

For the purpose of providing a variety of crystal patterns, different treatments prior to annealing have been hitherto proposed, as for instance pressing, rolling, extrusion and other similar operations to impart different modes of pressure to the material, thus causing crystal grains of different sizes to appear on the surface of the material. In the Japanese Pat. Publication No. lO956/l963, a sheet of material is subjected to rolling by a patterned roll having raised portions of different levels in the form of a relief, thus pressing the sheet with different pressures over the entire surface with the result that crystal grains of different sizes will appear on the sheet surface. Also, the crystal grains are produced on the surface of a vase or other annular products in the form ofa pattern by preshaping metal material into blanks or semi-manufactured goods under pressure, subjecting the blank to stress-relief annealing (annealing for primary recrystallization), shaping the blank thus annealed to the final shape as required, annealing the final blank for the growth of crystal grains (annealing for secondary recrystallization, and finally by etching the same.

The patterned article produced by the above methods, presents a pleasing appearance with respect to the ornamental requirements. However, the crystal pattern thus produced will be of two-dimensional or flat appearance.

SUMMARY OF THE INVENTION It has been discovered that large-sized crystal grains, whose lattices are generally curved with respect to the surface of the metal sheet, will when etched to expose such crystal grains on the surface of the metal sheet, present a three-dimensional or relief crystal pattern in appearance.

This invention is based on this discovery, and one object of this invention is to provide a metal article having a three-dimensional or relief crystal pattern in appearance.

Another object of this invention is to provide a method of making such a relief-patterned article.

The word, article herein used should be understood to include metal material of any form, such as sheet, plate, foil, or pipe; semi-manufactured metal goods and final metal products.

According to this invention, there is provided a relief-patterned metal article having a crystal pattern composed of crystal grains, at least a part of said crystal pattern being composed of large-sized crystal grains visible to the naked eye, the crystal lattice of each large-sized crystal grain or the lattice of each of selected large-sized crystal grains being curved per se, also being curved with respect to the surface of said article prior to etching.

Also, according to this invention there is provided a method of producing a relief-patterned metal article comprising the steps of: shaping a metal material or at least a part thereof by bending, punch stretching, deep drawing, squeezing or other deforming operations to produce a given curved or folded form; annealing the material above the recrystallization temperature to cause enlargement of crystal grains; leveling or shaping the material by bending, punch stretching, extruding, deep drawing, squeezing or other deforming operations such that it has local curvatures different from those of said given curved form; and then etching the material.

X-ray diffraction examination reveals that each of the large-sized crystal grains exposed on the surface of the relief-patterned article, according to this invention, has a lattice which is curved with respect to the surface. Each single large-sized crystal grain exposed on the metal surface will reflect light in different directions, and it will shine in a way similar to a polyhedron reflector when exposed to light.

BRIEF DESCRIPTION OF THE DRAWING This invention will become more apparent from the following description which will be given with reference to the accompanying drawings wherein:

FIG. 1 is a diagrammatic side elevation representing the surface ofa conventional patterned article having a two-dimensional or flat crystal pattern in appearance;

FIGS. 2 and 3 diagrammatically show the manner in which the crystal lattice of each large-sized grain is curved and the manner in which collimated rays will be reflected by the metal surface to present a threedimensional or relief pattern to the human eye;

FIGS. 4A and 4B are photographs of actual reliefpatterned articles according to this invention, whereas FIG. 4C is a photograph of a conventional patterned article;

FIG. 5 is a photograph ofa relief-patterned article according to this invention;

FIG. 6 is a photograph showing the shape which the material may take in producing a relief-patterned article according to this invention; and

FIGS. 7 to 12 show different relief-patterned articles according to this invention.

DETAILED DESCRIPTION Referring to FIG. 1, there is shown a diagrammatic sectional view of the surface of a conventional crystalpatterned metal article. The surface of the metal article prior to the etching treatment is indicated by the dotted, planar line. Sections I, II and III represent different crystal grains, and the fine grid intersections in each of these sections indicate a crystal lattice. If the metal surface is subjected to etching, the part lying between the dotted line and the solid line will be removed from the metal surface, thus leaving a square-irregular surface in the microscopic sense. The inclination of individual microsquares with respect to the original surface (dotted line) simply depends on the crystal orientation. If collimated rays a /a l are projected onto the squareirregular surface of the metal, the collimated rays will reflect on individual crystal grains I, II and III at different angles, thus presenting a crystal pattern to the human eye. As is apparent from FIG. I. the collimated rays will reflect from the square-irregular surface of a single crystal grain I, II or III at the same angle, thus causing the entire area of the single crystal grain to appear with the same intensity of brightness. As a result, the entire surface of the metal will present a twodimensional or flat crystal pattern.

According to this invention, the metal sheet is curved, and the sheet thus curved is annealed to cause the crystal grains to enlarge. The crystal lattice of each grain is not deformed (or curved) in this stage of process, as shown in FIG. 2. The metal blank is then flattened or curved in an opposite or different direction from the previous deformation. Then, the lattice of each crystal grain will be curved as shown in FIG. 3. Then, the metal blank is subjected to etching to leave the square-irregular surface as indicated by the thick solid line. In FIG. 3 the crystal lattice is shown as continuously curved. However, the lattice may be curved, partially or wholly, e.g. in the form of a polygon.

In constrast to the two-dimensional or flat pattern appearing on the metal surface as shown in FIG. I, individual micro-squares in the same crystal grain are inclined at different angles with respect to the surface (dotted line), thus causing the collimated rays a 0 or a;, falling on the grain to reflect at different angles as indicated at a,, a' or a' Thus, a single crystal grain will present a shiny mosaic appearance having different intensities of brightness. Due to the crystal lattice which is curved with respect to the metal surface, each crystal grain appears to be raised from or depressed below the metal surface. Thus, the metal surface will present a relief crystal pattern. The concave, square-irregular section of the grain I as shown in FIG. 3 will appear as if it were depressed.

The direction and curvature of the crystal lattice depends on the degree of variation from the first shaping prior to annealing to the second shaping subsequent to annealing.

Taking the final shape of the metal article into consideration, a proper shape is given to the metal mate rial, prior to annealing, so that a crystal pattern composed of crystal grains having a variety of curved lattices may be caused to appear on a given part of the surface or over the whole area thereof.

Generally speaking, the strength of the metal if annealed, will be lowered, and for this reason the conventional patterned metal is, in fact, useless in making metal articles sufficiently rigid in use. The second shaping subsequent to annealing, in the process according to this invention, however, will be useful in hardening the material, fully compensating for the strength of the material lost in the first annealing. The reliefcrystal pattern will not be damaged even if the material is subjected to a drastic second shaping of as much as 30%.

The material which can be used in making patterned articles according to this invention may be for instance, copper, brass, stainless steel, aluminum, zinc, tin or alloys thereof. The material may be of any shape, as for instance, sheet, foil, rod, or pipe.

If the surface of the relief-patterned article is finally treated by applying a transparent lacquer, by electric plating or by anodic oxidation, the relief-pattern will clearly appear without losing the details thereof.

This invention will be better understood from the Examples given hereafter.

EXAMPLE l An aluminum plate (0.5mm thick) was wound around a rod (20mm in diameter), and then the rod was removed. The wound plate was annealed at a temperture above 560C for 30 minutes, thus making the crystal grains large. When the plate has cooled, it was unwound and leveled. The plate was etched in an HCl- HNO solution, thus causing large-size grains to appear in the form of a pattern as shown in FIG. 4A.

Another aluminum plate (0. 1 5mm thick) was wound around a rod 5mm in diameter), and then the rod was removed. The plate thus wound was annealed at a temperature above 560C for 30 minutes, thus making the crystal grains large. When the plate became cool, it was unwound and leveled. The plate was etched in an HCl- HNO solution. The final product was shown in FIG. 4B.

For the sake of comparison, a crystal patterned aluminum plate was made according to the conventional method as described previously and is shown in FIG. 4C. As seen from FIG. 4C, each irregular section corresponding to a single large-sized grain shines evenly, and therefore the irregular sections together present a twodimensional mosaic pattern to the human eye. In contrast to this, as seen from FIGS. 4A and 43, each irregular section appearing on the surface of the patterned article according to this invention shines unevenly. More specifically, each irregular section corresponding to a single grain has bright and shady parts, and it presents a concave or convex appearance.

As mentioned earlier, the appearance of the relief mosaic pattern is attributable to the fact that the crystal lattice is curved per se, and also curved with respect to the surface level. As is apparent from FIGS. 4A, 4B and 4C, the appearance of the grain domain on the metal article according to this invention (FIGS. 4A and 4B) is totally different from the appearance of the grain domain on the conventional metal article (FIG. 4C). This is because the direction of crystal growth is controlled by the preshaping prior to annealing, and for this reason this invention makes it possible to provide a variety of mosaic patterns by properly preshaping the metal material prior to annealing.

EXAMPLE 2 An aluminum sheet (0.6mm thick) was wound in the form of a funnel and annealed at 600C for one hour.

After the funnel had cooled, it was unwound, and leveled. The meterial was etched in an HCl-HNO, solution, thus causing grains to appear on the metal surface. The final product is shown in FIG. 5. As seen from this photograph, the relief pattern extends radially from one corner of the plate to the other corners, presenting a variety of brightnesses and shadings. This pattern has a floating appearance when a viewer sweeps his eyes over the patterned surface. This floating appearance enhances the ornamental effect.

EXAMPLE 3 A square aluminum plate (0.5mm thick) was folded in the form as shown in FIG. 6, and the metal plate, thus folded, was annealed at a temperature above 600C for l hour. After the plate had cooled, it was unfolded and leveled. Then, the square plate was etched in an HCl-HNO- solution. The reliefpatterned article thus obtained is shown in FIG. 7. The pattern is composed of a radial symmetry of bright and shady stripes.

EXAMPLE 4 An aluminum foil (100 microns thick) was partially buckled, and preshaped in the form as shown in FIG. 8A. It was annealed at 580C for ID minutes. After cooling, it was stretched into the original form, and leveled. Finally, it was etched in an I-ICl-HNO solution. The relief-patterned article thus obtained is shown in FIG. 88.

Another aluminum foil was partially crimped, and was treated in the same way as above mentioned. The resultant article is shown in FIG. 8C. In either case, grains appear at the folds of the foil, rising or sinking from the remaining part of the foil in appearance, thus constituting a clear relief pattern.

EXAMPLE 5 A pure aluminum sheet A1085 (0.5mm thick) was first subjected to stress-relief annealing. Then, the sheet was wound around an iron rod (40mm in diameter) in a given direction, and the rod was removed. The rolled sheet was annealed at a temperature above 500C, thus causing grains to enlarge.

After cooling, the sheet was unwound and leveled, and then it was again wound around an iron rod (20mm in diameter) in the direction transverse to the original direction. The iron rod was removed. and then the rolled sheet was annealed at about 580C, thus causing the grains to enlarge. After cooling, the rolled sheet was unwound and leveled. The flat sheet was etched in an HCl-HNO solution, causing crystal grains to appear on the sheet surface. The relief-patterned article thus obtained is shown in FIG. 9.

EXAMPLE 6 An aluminum plate (0.5mm thick) was wound around an iron rod (40mm in diameter), and then the rod was removed. The rolled plate was annealed at a temperature of about 500C, causing the grains to enlarge. After cooling, the plate was unwound, and then it was folded radially at the center of the plate. The plate thus folded was annealed at 580C, thus causing grains to enlarge. After cooling, the plate was leveled. The plate was etched in an HCl-HNO resulting in the exposure of the grains. The resultant product is shown in FIG. 10 and is composed of a relief-patterned sheet having the pattern of large-sized grains, each grain growing in a different direction and having a different curvature of crystal lattice.

EXAMPLE 7 The same aluminum sheet as used in Example I was subjected to slight stressing without causing deformation, and then the sheet thus treated was annealed at a temperature above 500C, thus causing the crystal grains to enlarge. After cooling, the sheet was wound around an iron bar (5mm in diameter), and then the bar was removednThe rolled sheet was annealed at about 580C, thus allowing the crystal grains to enlarge. Then, the rolled sheet was unwound, and leveled. The sheet thus leveled was etched in an HCl-HNO solution, thus allowing crystal grains to appear on the sheet surface. The product is shown in FIG. 11 and, has a crystal pattern composed of flat-looking and relieflooking grains in coexistence.

EXAMPLE 8 After being stress-relief annealed, an aluminum foil A1050 (0.l5mm thick) was crimped at the center thereof, and the foil thus crimped was annealed at a temperature of about 500C causing the grains to enlarge. After cooling, the foil was extended and smoothed into the original shape. The foil was wound around an iron rod (5mm in diameter), and the rod was removed. The rolled foil was annealed at a temperature of from 540 to 560C, thus causing the grains to enlarge. Then, the foil was unwound and leveled. Finally, the foil was etched in an HCl-HNO; solution, allowing grains to appear on the surface of the foil. As shown in FIG. i2, discrete, striped grains grown in a given direction and collective, capillary grains grown in all directions appear together and constitute a relief pattern in appearance.

As is apparent from the above, the method of manufacturing relief-patterned articles according to this invention essentially comprises, the steps of: at least partially curving a metal material; annealing the metal material in its curved state; leveling or shaping the annealed material in a different or opposite sense to the previous curving; and finally etching the material. The degree of deformation, the particular shape caused thereby, the degree of stressing, the annealing temperature, the annealing time, the kind of etching agent, the etching period and other factors are properly selected, or determined so as to meet particular requirements of appearance.

The crystal pattern of the metal article of this invention is characteristic of:

1. each large-sized grain appears as if raised from or depressed below the surface of the material, thus providing together a relief pattern in appearance.

2. each single grain appearing on the surface of the material has shiny and shaded parts, thus providing, in combination with the relief appearance, a composite effect on the variety of the pattern.

3. shiny or shaded parts will vary with the angle of view, and therefore the pattern will appear to change to a viewers eyes while the viewer is moving, thus. presenting a striking appearance.

4. desired or selected parts of the metal surface can be made in relief.

The relief-patterned article according to this inven tion is particularly useful for interior or exterior decoration for houses or vehicles and in decorated articles. A relief-patterned foil (0.05-0.3mm thick) can be used to cover the surface of any kind of substrate material. A material so covered can be used in a variety of ornamental applications. In particular, aluminum or tin foils can be used as a packing material.

What is claimed is:

l. A relief-patterned metal article comprising a crystal pattern composed of a plurality of crystal grains, at least some of which are large-sized crystal grains visible to the naked eye, at least selected of the large-sized crystal grains having a curved crystal lattice which is curved with respect to an outer surface of the article, said surface being etched and the curvature of the crystal lattice being sufficient for providing a visible relief pattern in the surface appearance of the article.

2. A relief-patterned metal article according to claim 1 wherein said crystal lattice is continuously curved throughout each of the grains.

3. A relief-patterned metal article according to claim I wherein said outer surface is initially flat.

4. A method of producing a relief-patterned metal article comprising: shaping a metal material into a given deformed form; annealing the thus deformed material above the recrystallization temperature to cause enlargement of crystal grains; reshaping the material into a form in which it has a local curvature different from that of said given deformed shape to produce a curved crystal lattice for said grains; and then etching the surface of the material.

5. A method according to claim 4 wherein the steps of shaping the metal material and annealing the material above the recrystallization temperature for enlargement of the crystal grains are repeated at least once for producing a desired crystal pattern.

6. A method according to claim 4 wherein the deformed form of the shaped metal is curved and the subsequent shaping of the material produces a flat surface.

7. A method of producing a relief-patterned metal article comprising: deforming a metal material such that the material thus deformed is flat; annealing the flat material above the recrystallization temperature to cause enlargement of crystal grains; shaping the flat material into a given curved shape; annealing the material above the recrystallization temperature for further enlargement of crystal grains; deforming the material into a shape which is different from said given curved shape to produce a curved crystal lattice for said grains; and then etching the material.

8. A method according to claim 7 wherein the step of deforming the metal material so that it is flat, comprises leveling, rolling, bending-unbending, or stretch- 9. A method according to claim 4 wherein the different local curvature of the reshaped material is in opposite sense to that produced by the first shaping.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5,89l,+72 Dated June 24, 1975 lnventofls) Kiyota Yoshida et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Item [50] "May 29, 1975 Japan ua- 55218" should read May 29, 1972 Japan fi- 55218 Signed and Sealed this twenty-seventh D3) Of January 1976 [SEAL] Arrest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ujParenrs and Trademarks 

1. A RELIEF-PATTERNED METAL ARTICLE COMPRISING A CRYSTAL PATTERN COMPOSED OF A PLURALITY OF CRYSTAL GRAINS, AT LEAST SOME OF WHICH ARE LARGE-SIZED CRYSTAL GRAINS VISIBLE TO THE NAKED EYE, AT LEAST SELECTED OF THE LARGE-SIZED CRYSTAL GRAINS HAVING A CURVED CYRSTAL LATTICE WHICH IS CURVED WITH RESPECT TO AN OUTER SURFACE OF THE ARTICLE, SAID SURFACE BEING ETCHED AND THE CURVATURE OF THE CRYSTAL LATTICE BEING SUFFICIENT FOR PROVIDING A VISIBLE RELIEF PATTERN IN THE SURFACE APPEARANCE OF THE ARTICLE.
 2. A relief-patterned metal article according to claim 1 wherein said crystal lattice is continuously curved throughout each of the grains.
 3. A relief-patterned metal article according to claim 1 wherein said outer surface is initially flat.
 4. A method of producing a relief-patterned metal article comprising: shaping a metal material into a given deformed form; annealing the thus deformed material above the recrystallization temperature to cause enlargement of crystal grains; reshaping the material into a form in which it has a local curvature different from that of said given deformed shape to produce a curved crystal lattice for said grains; and then etching the surface of the material.
 5. A method according to claim 4 wherein the steps of shaping the metal material and annealing the material above the recrystallization temperature for enlargement of the crystal grains are repeated at least once for producing a desired crystal pattern.
 6. A method according to claim 4 wherein the deformed form of the shaped metal is curved and the subsequent shaping of the material produces a flat surface.
 7. A method of producing a relief-patterned metal article comprising: deforming a metal material such that the material thus deformed is flat; annealing the flat material above the recrystallization temperature to cause enlargement of crystal grains; shaping the flat material into a given curved shape; annealing the material above the recrystallization temperature for further enlargement of crystal grains; deforming the material into a shape which is different from said given curved shape to produce a curved crystal lattice for said grains; and then etching the material.
 8. A method according to claim 7 wherein the step of deforming the metal material so that it is flat, comprises leveling, rolling, bending-unbending, or stretching.
 9. A method according to claim 4 wherein the different local curvature of the reshaped material is in opposite sense to that produced by the first shaping. 